Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

OTHER MODES OF THE 8255

BSR

(Bit Set/Reset)

Mode

‰A unique feature of port C

¾The bits can be controlled individually

‰BSR mode allows one to set to high or low any of the PC0 to PC7, see figure 15-12.

D7 D6 D5 D4 D3 D2 D1

D0 S/R

Bit Select

x

x

x

(^0) BSRMode
Figure 15-12. BSR Control Word
Not UsedGenerally Set = 0
000 = Bit 0 100 = Bit 4001 = Bit 1 101 = Bit 5010 = Bit 2 110 = Bit 6011 = Bit 3 111 = Bit 7
Set=1Reset=0